Hydroxylation of unsaturated compounds



hydrogen peroxide and a novel catalyst. lanother'of its aspects'the invention relates to the production of .polyhydroxy alcohols and acids by for a long time.

prepare ethylene glycol.

Patented June 5, 1951 IIYDROXYLATION OF'UNSATURATED COMPOUNDS Chester M. Himel, Palo Alto, Calif; and. Lee 0.

Edmonds, Bartlesville, Okla,v assignors to Phillips Petroleum Company, a corporation of Dela- No Drawing. Application May 25,1949, Serial No..95,'386

Claims.

This invention relates to the hydroxylation of unsaturated compounds. In one of its aspects the invention relates to the hydroxylation of organic compounds containing at least one olefinic linkage or bond permolecule. In another of its aspects the invention relates to the hydroxylation of an unsaturated compound using In still hydroxylation of olefinic hydrocarbons and unsaturated organic acids, respectively, using hydrogen peroxide-and employing a novel catalyst whichhas permitted attainment of important advantages which :are'set forth below. In one embodiment :of the invention :polyhydroxy alcohols and polyhydroxy acids are prepared by hydroxylation of olefini'c linkages in compounds containing thesame using hydrogen peroxide and a novelacatalyst comprising a selected alkyl formate as set forth more fully below.

The hydroxylation of acompound containing an olefinic linkage has been known and practiced Thus, in one method ethylene has been treated with alkaline permanganate to In another method hydrogenperoxide and acetic acid have been used to prepare ethylene glycol.

In copending application Serial No. 744,526,

filed April 28, 1947,.by Chester M. Himel and Lee O. Edmonds, there is disclosed andclaimed a process for theproduction of a polyhydroxy organic material which comprises treating an ali- .phatic type organic material containing at least two olefinic linkages with hydrogen peroxide in 1 presence of formic acid as catalyst.

In one or more of the foregoing processes either high concentrations of hydrogen peroxide are requiredxor recovery ofithe product isrendereddi'flicult because of the formation of 'an azeotrope.

Thus, with acetic acid as a catalyst the concentration'of'hydrogenperoxide required is generally above 60 per cent. With formic acid, which will catalyze' the reaction with a lower concentration of hydrogen peroxide, there is formed a maximum boiling water azeotrope comprising about 70 per cent formic acid and boiling at about 108 C. Therefore, when formic acid has been employed as the catalyst, upon distillation of the reaction mixture, water will be removed until the azeotropic concentration of the acid has been reached and from that stage of the distillation the desired hydroxy'lated product will be in intimate contact with '70 per centformic acid at a temperature of about 108 C. Thisprolonged contact of 2 the desired .hydroxylated product with the TOper cent formic acid at th'exsaid temperature of 108C. causes extensive *esterification of the desired product. It is at once apparent, from the foregoing, that recovery of both the desired product and of the catalystis "greatly reduced and dithcult.

One of the objects accomplished'bythe present invention is the provision of a process for the hydroxylation of olefinic or'unsaturatedorganic compounds using hydrogen peroxide inthepresence of a catalyst novel lfOl"thlS reaction which catalyst not-only permits'useof an hydrogen peroxidehaving a low concentration butat thesame time permits readyand easy recovery'ofboth the desired product'and the catalyst by'simple distillation without contact of the desired product with an acidmaterial at an elevated temperature, thereby avoiding entirely the esterification encountered inthe prior art' as well as its attendant eifect upon both the yield and recovery of the desired product and upon therecovery of the-acid there employed.

As stated the novel catalyst employed in the process of the .invention is a selected alkyl formate. The catalysts of the invention comprise alkyl formates boilin below about C. Thus, methylformate, ethyl formate and the propyl formates are within the operative scope of the invention.

Thus, according to the present invention'the're is provided aprocess for the hydroxylation of an unsaturated organic compound. having at least one olefinic linkage by treating said compound with. hydrogen peroxide in the presence of a cata lyst comprising .a low boiling alkyl formate, ;for

example, methyl formate, ethyl "formate or a propyl formats. 7

With the catalyst of-this. invention a high degree of conversion .is vrealized and, as stated,..hydrogen peroxide reagent of. low concentration can be used and the recovery of both the desired product and the catalyst is accomplished with case.

The quantity of catalyst employed will be in the range of fromabout 5to about 200 mol percent, preferably 50 to 100 mol per cent, based upon the hydrogen peroxide-reagentused. l

The quantity of hydrogen peroxideusedtwi-ll be at least about one mol for 'each olefinic link:- age to be hydroxylated. Preferably, an excess of from about 10 to20 per cent of hydrogen peroxide will be used. The hydrogen peroxide-can be used 'as an aqueous solution havinga-"con'cen- .structure compound, for=example styrene.

ide (weig ht per cent solution).

mol of. 3butene-l,2-diol.

even with highly concentrated hydrogen perox-;

ide, reaction velocity is reduced to a negligible figure. We have found that by operating with aqueous hydrogen peroxide having a concentration of from five to fifteen weight per cent and with the amount of catalyst'being from I 50 to 100 mol per cent based on'the peroxide, commerciallyfeasible reaction rates can be realized.

According to a preferred embodiment of our process, the catalyst is admixed with the olefinic compound to be hydroxylated and charged to a suitable reactor. The hydrogen peroxide is then introduced and the reactor sealed. During the reaction period, usually ironilZ to 48 hours, the .mixture is agitated at a'temperaturein arrange between; and 100 C. The'reaction mixture is then removed and fractionated. The catalyst,

having .a .lowboiling point, is recovered almost quantitatively, after which the water, and finally the product distills.

; The present invention is applicable to the hy- "droxylati'on of olefinic linkages in monoolefins, 'diolefins, unsaturated fatty acids, unsaturated alcohols, and thelike. It isnalso. applicable to thehydroxylation' of aliphatic olefinic compounds whicli have been substituted, with a cyclic or ring Also, a' cyclic olefinic compound may be employed which has been substituted with a saturated compound, for example-methyl or ethyl cyclohexene. Butadiene can be hydroxylated to erythritol and/or butene diol; monoolefins to glycols, cyclic olefins such as cyclohexene to'the corresponding diol, unsaturated fatty acids to dihydroxy carboxylic acids, etc.

Example I A. reactor was charged with 2.78 mols of butadiene and 6.0.mols of methyl formate. To this mixture was added 6.0 mols of hydrogen perox- The reactor was then sealed and the contents agitated at C. At the end of a 24 hour reaction period ,the reactor was opened and the contents fracftionated. Recovery of the methyl vformate catalyst was substantially quantitative; The hydroxylated product comprised 0.80 mol of mesoerythritol, 0.80 mol of dl-erythritol, and 0.42

Utilization of butadiene was '73 per cent of theoreticall 1 Example 'I and four mols of hydrogen peroxide were'charged (10 weight per cent solution). The run was continued for '24'hours' at 50 C. By fractionation of the reaction mixture the catalyst was recovered together with 1.? mols of unreacted butadiene. The product comprised 0.40 mol of mesoerythritol, 0.40 mol of dl-erythritol and 1.0 mol of 3-butene-1,2-diol.-

Example I II Q Hydroxylation of cyclohexene was carried out .in. a manner-similar to that described for ,buta- I melting point of 116117 C.

diene in Example I. Five per cent excess hydro- 7 2-butene was hydroxylated according to the procedure of Example III. The reaction time was 24 hours and the temperature 50 C. The

dihydroxy butane product had a refractive index n 1.4325 and boiled at 50-56 C. under 1 mm. pressure. Theyield was per cent of theoretical.

Example V l-butene was hydroxylated according to the procedure of Example III. The reaction time was 24 hours and the temperature 50 C. The

diol product boiled at 68 C. at 0.4 mm; and hada refractive index of n 1.4375. The bis-phenylurethane derivative was prepared and had-a Example VI Styrene was hydroxylated using the procedure of Example III. The yield of diol obtained was about 40 per cent of theory. Wherirecrys'tallized from hexane the product had a melting point of 62-6? C; e

v V Reasonable variation and modification are pos- 'sible Within the scope of the appended claims to the invention the essence of which is that an unsaturated organic compound having at least one olefinic linkage has beenhydroxylated with low hydrogen peroxide concentrations to obtain high yields of desired products without difiiculty and with recovery of the catalyst as aforesaid.

We claim: 1. The hydroxylation of an organic compound having at least one olefinic linkage by contacting it with hydrogen peroxide in the presence of .a low boiling alkyl formate. 2. The hydroxylation of an aliphatic compoun having at least one olefinic linkage by contacting it at a temperature in the range 25-100 C. with hydrogen peroxide having a concentration of from 5-75 weight per cent in the presence of a low boiling alkyl formate.

3. The hydroxylation of a substituted compound having at least one olefinic linkage by contacting it at a temperature in the range 25-100 C. with hydrogen peroxide having a concentration of from 5-75 weight per cent in the presence of a low boiling alkyl formate.

i. The hydroxylation of a cyclic compound having. at least one olefinic linkage 'by contacting itat a temperature in the range 25-100 C. with hydrogen peroxide having :a concentration of from 5-75 weight per cent in the presence of a low boiling alkyl formate.

5. The process of claim 1 wherein theorganic compound is butadiene, the temperature is in the range 25-100 0., at least one mol of hydrogen peroxide is present per olefinic linkage to be hydroxylated and 5-200 mol per cent of the alkyl formate, based upon the hydrogen peroxide reagent used, is employed.

6. The process of claim 5 wherein the alkyl 7 formate is methyl formate.

'7. The process of claim 1 wherein the organic compound is a butene, the temperature'is in the range 25-100 C., at least one mol of hydrogen peroxide is present per olefinic linkage to be hydroxylated and 5-200 mol per cent of the alkyl formate, based upon the hydrogen peroxide reagent used, is employed.

3. The process of claim '7 wherein the alkyl formats is methyl formate.

9. The process of claim 1 wherein the organic compound is styrene, the temperature is in the range 25-100" 0., at least one mol of hydrogen peroxide is present per olefinic linkage to be hydroxylated and 5-200 mol per cent of the alkyl formate, based upon the hydrogen peroxide reagent used, is employed.

10. The process of claim 9 wherein the alkyl formate is methyl formate.

11. The process of claim 1 wherein the organic compound is cyclohexene, the temperature is in the range 25-100 0., at least one mol of hydrogen peroxide is present per olefinic linkage to be hydroxylated and 5-200 mol per cent of the alkyl formate, based upon the hydrogen peroxide reagent used, is employed.

12. The process of claim 11 wherein the alkyl formate is methyl formate.

13. A process for the hydroxylation of an organic compound having at least one olefinic linkage which comprises the steps of contacting said organic compound with hydrogen peroxide in the presence of a low boiling alkyl formate for a time surficient to form the desireihydroxylated compound and then distilling and fractionating the reaction mass thus produced to recover said hydroxylated compound and said low boiling alkyl formats thereby avoiding substantially any esterification.

14. The process of claim 13 wherein the temperature during the hydroxylation is in the range 25-100 C., hydrogen peroxide having a concentration of 5-75 weight per cent is employed, and 5-200 mol per cent of the alkyl formate is used.

15. A process according to claim 14 wherein said organic compound is butadiene.

CHESTER M. HIMEL. LEE 0. EDMONDS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,138,917 Grun Dec. 6, 1938 2,304,064 Scanlan et al. Dec. 8, 1942 2,373,942 Bergsteinsson Apr. 17, 1945 2,414,385 Milas Jan. 14, 1947 2,437,648 Milas Mar. 9*, 1948 OTHER REFERENCES Jour. Am. Chem. Soc., vol. 6'7, pages l7869 (1945) (Swern et al.).

Jour. Am. Chem. Soc., vol. 68, pages 1504-? (1946) (Swern et a1.). 

1. THE HYDROXYLATION OF AN ORGANIC COMPOUND HAVING AT LEAST ONE OLEFINIC LINKAGE BY CONTACTING IT WITH HYDROGEN PEROXIDE IN THE PRESENCE OF A LOW BOILING ALKYL FORMATE. 